Recording medium, recording method, and recording apparatus

ABSTRACT

Payload  0  as a header is recorded to a head of a UDI area. In the case of recording payload  0  and other payloads, each of them is quintuple-recorded in order to take a countermeasure against errors. Other payloads such as payload  1  and the like are recorded after payload  0 . In the case of quintuple-recording, the payloads of the same payload number are collectively quintuple-recorded. AUDI is recorded from a position after one second from start time S. The payloads are arranged in positions at 12-frame intervals. Thus, the five data which is multiple-written are not arranged in the radial direction of a disc but widely distributed onto tracks. Error resistance is improved. An interval of data is set to an optimum value in accordance with the number of multiple-writing times, a linear velocity, a recording position on the disc, and the like.

TECHNICAL FIELD

The invention relates to a recording medium, a recording method, and arecording apparatus which are applied when data is multiple-written ontothe recording medium.

BACKGROUND ART

A method whereby, in the case of recording desired data onto a recordingmedium, same data is repetitively recorded (multiple-writing) to improveresistance of the data to errors has been known. Owing to themultiple-writing, if there is at least one errorless data among aplurality of data, such errorless data can be used as data without anerror. Hitherto, sufficient consideration is not given to a recordingposition of the data which is multiple-written.

DISCLOSURE OF INVENTION

According to an embodiment of the invention, there is provided arecording apparatus comprising:

detecting means for detecting management data for managing predetermineddata from a disc-shaped recording medium on which said management datahas previously and repetitively been recorded in the circumferentialdirection at predetermined intervals;

recording means for recording data onto the recording medium; and

recording control means for controlling the recording means so as torepetitively record the predetermined data in the circumferentialdirection at predetermined intervals on the basis of the management datadetected by the detecting means.

According to the invention, a plurality of data to be multiple-writtenis recorded so as to be distributed as much as possible on the recordingmedium, so that error resistance to a scratch on the disc, a bursterror, or the like is improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram for explaining several examples in thecase where the invention is applied to a disc having concentric tracks.

FIG. 2 is a schematic diagram for explaining two examples in the casewhere the invention is applied to a disc having a spiral track.

FIG. 3 is a schematic diagram for explaining two examples in the casewhere the invention is applied to a card-shaped recording medium.

FIG. 4 is a schematic diagram for explaining a recording pattern of aconventional CD and a structure of the CD.

FIG. 5 is a schematic diagram for explaining manufacturing steps of adisc in an embodiment of the invention.

FIG. 6 is a schematic diagram for explaining a frame format of the CD.

FIG. 7 is a schematic diagram for explaining a subcode frame of asubcode in a Q channel.

FIG. 8 is a schematic diagram showing a format of Mode 1 to record timeinformation as a subcode in the Q channel.

FIG. 9 is a schematic diagram for explaining a format of a subcode in aTOC area.

FIG. 10A is a schematic diagram showing a data format of a UDIconstructed by a subcode frame consisting of 98 frames.

FIG. 10B is a schematic diagram showing a data format of a payload 0 asa header.

FIG. 11A is a schematic diagram showing a UDI index comprising a payloadnumber (6 bits) indicative of the number of the payload and a payloadstatus (2 bits).

FIG. 11B is a diagram showing definition of the payload number and thepayload status.

FIG. 12A is a schematic diagram showing a data format of a payload 0.

FIG. 12B is a diagram showing a value in each field of the payload 0.

FIG. 13A is a schematic diagram showing a data format of a P-payload inthe case where there is no ECC.

FIG. 13B is a schematic diagram showing a data format of the P-payloadin the case where there is an ECC.

FIG. 14A is a schematic diagram showing a data format of an R-payload inthe case where there is no ECC.

FIG. 14B is a schematic diagram showing a data format of the R-payloadin the case where there is an ECC.

FIG. 15 is a schematic diagram for use in explanation of a recordingmethod of a UDI in the embodiment of the invention.

FIG. 16 is a schematic diagram for use in explanation of a recordingmethod of a UDI in the embodiment of the invention.

FIG. 17 is a schematic diagram for use in explanation of an example of alayout in a UDI area.

FIG. 18 is a block diagram showing an example of a construction of amastering apparatus according to an embodiment of the invention.

FIG. 19 is a block diagram showing an example of a construction of a UDIrecording apparatus according to an embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The invention will now be described hereinbelow. FIGS. 1 and 2 showseveral examples in the case where the invention is applied to adisc-shaped recording medium (simply referred to as a disc). FIG. 1shows the case of multiple-writing predetermined data A to the disc onwhich tracks have been formed concentrically. Assuming that the numberof multiple-writing times is set to n, same data A₁, A₂, . . . , A_(n)are recorded onto the disc. Examples of n=2, n=3, n=4, n=5, and n=6 areshown in FIG. 1.

An angle interval θ of a plurality of data which are multiple-written isselected to be (θ=360°/n). That is, it is selected to be (n=2: θ=180°),(n=3: θ=120°), (n=4: θ=90°), (n=5: θ=72°), and (n=6: θ=60°). It is notnecessary that a value of the angle interval θ coincides accurately witheach of those values but it is sufficient that it almost coincides witheach of those values.

By selecting the value of the angle interval θ as mentioned above, adistance between the multiple-written data on the track can be maximizedand it is possible to prevent a plurality of data from being arranged inthe radial direction. Thus, data reproducing ability against errors dueto a scratch, fingerprints, or the like on the disc and a burst errorcan be improved.

Although the data A₁ to A_(n) have been recorded on the same track inFIG. 1, the data A₁ to A_(n) can be also recorded onto different tracks.When n=5, the angle interval θ can be selected to be about 144° or about216° instead of 72°. That is, it is preferable to arrange the data A₁ toA₅ at the angle intervals of about 72° irrespective of their order.

FIG. 2 shows the examples in which the invention is applied to the casewhere a track is spirally formed on a disc. The case of n=5 is shown inFIG. 2. In one of the examples, the data A₁ to A₅ have been sequentiallyrecorded at the angle intervals of about 72°. In the other example, thedata A₁ to A₅ have been sequentially recorded at the angle intervals ofabout 216°.

The invention is not limited to the disc but can be applied to arectangular recording medium (card-shaped recording medium). FIG. 3shows one example and another example of the case of multiple-writing(for example, n=4) in such a case. When a plurality of tracks are formedalmost in parallel onto the card-shaped recording medium, the data A₁ isrecorded onto the nth track, the data A₂ is recorded onto the (n+1)thtrack, the data A₃ is recorded onto the (n+2)th track, and the data A₄is recorded onto the (n+3)th track, respectively. Assuming that a lengthof one track is equal to L, the data is recorded in the track directionat data intervals of about (L/n) (in the example shown in the diagram,L/4). An interval between the data A₄ which is recorded last and thefirst one (A₁′) of the data to be subsequently multiple-written is alsoset to about (L/4).

In another example shown in FIG. 3, the data to be multiple-written isrecorded onto the different tracks and multiple-written in the trackdirection at intervals of about (L/(n−1)) (in the example shown in thediagram, L/3). In this another example, the data which is recorded lastis positioned at the edge of the track. Further, although the recordingmedium has a rectangular shape, the invention can be also applied to arecording medium on which concentric tracks or a spiral track is formed.

An embodiment in which the invention is applied to the case where discidentification information (hereinafter, referred to as UDI) is recordedonto the disc-shaped recording medium will be described hereinbelow. TheUDI is recorded so that it can be read out by, for example, an existingCD player or CD-ROM drive. First, a structure of an optical disc, forexample, a CD will be described for easy understanding of theembodiment.

FIG. 4 enlargedly shows a part of the existing CD. Concave portionscalled pits and lands on which no pit is formed are alternately formedon tracks of a predetermined track pitch Tp (for example, 1.6 μm).Lengths of the pits and the lands lie within a range of 3 T to 11 T. Tdenotes a shortest inverting interval. A laser beam is irradiated to theCD from the lower side.

The CD has such a structure that a transparent disc substrate 1 having athickness of 1.2 mm, a reflective film 2 formed thereon, and aprotective film 3 formed on the reflective film 2 are sequentiallylaminated in order from the lower side to which the laser beam isirradiated. A film having high reflectance is used for the reflectivefilm 2. The CD is a read-only disc and, as will be explainedhereinafter, after the reflective film 2 is formed, the information(UDI) is recorded to the reflective film 2 by using the laser beam.

A flow of manufacturing steps of the CD as mentioned above will bedescribed with reference to FIG. 5. In step S1, a glass mother disc inwhich a glass plate is coated with a photoresist as a photosensitivematerial is rotated by a spindle motor. The laser beam which is turnedon/off in accordance with a recording signal is irradiated onto aphotoresist film and a master disc is formed. A developing process isexecuted to the photoresist film. In the case of a positive type resist,photosensed portions are fused and a concave/convex pattern is formed onthe photoresist film.

One metal master disc is formed by an electroforming process for platinga photoresist mother disc (step S2). A plurality of mother discs areformed from the metal master disc (step S3). Further, a plurality ofstampers are formed from the mother discs (step S4). A disc substrate isformed by using the stamper. A compression molding, an injectionmolding, a photo-curing method, or the like has been known as a formingmethod of the disc substrate. The reflective film and the protectivefilm are formed in step S6. According to the conventional discmanufacturing method, the CD is manufactured by further performing labelprinting.

In the example of FIG. 5, step S7 of irradiating the laser beam onto thereflective film and additionally recording information is added. In theland on the reflective film, atoms are moved by a heating process(thermal recording) in which the laser beam is irradiated, a filmstructure or crystallization changes, and reflectance of this portiondecreases. Thus, after the irradiation of the laser beam, even in theland, an amount of return laser beam is small and such a portion isrecognized in a similar way to a pit by a reading apparatus. By usingsuch a phenomenon, information can be recorded. In this case, a materialwhose reflectance is changed by the laser irradiation is used for thereflective film. The reflective film is not limited to the materialwhose reflectance decreases but a material whose reflectance increasesby the recording can be used.

Specifically speaking, the reflective film is constructed by an alloyfilm Al_(100-x)X_(x) of aluminum. At least one or more kinds of elementsamong Ge, Ti, Ni, Si, Tb, Fe, and Ag are used as “X”. A compositionratio “x” in the Al alloy film is selected to be a value in a range of5<x<50 [atom %].

The reflective film can be constructed by an Ag alloy film ofAg_(100-x)X_(x). In this case, at least one or more kinds of elementsamong Ge, Ti, Ni, Si, Tb, Fe, and Al are used as “X”. A compositionratio “x” in the Al alloy film is selected to be a value in a range of5<x<50 [atom %]. The reflective film can be made of, for example, amagnetron sputtering method.

For example, in the case where a reflective film made of an AlGe alloyis formed so as to have a film thickness of 50 nm and the laser beam isirradiated from the transparent substrate or the protective film sidethrough an objective lens, when a composition ratio of Ge is equal to 20[atom %] and a recording power is equal to 6 to 7 [mW], the reflectancedeteriorates by about 6%. When the composition ratio of Ge is equal to27.6 [atom %] and the recording power is equal to 5 to 8 [mW], thereflectance deteriorates by about 7 to 8%. Such a change in reflectanceenables the additional recording to the reflective film.

Further, FIG. 6 shows a data construction of one frame of the signal forthe conventional CD. In the CD, a parity Q and a parity P eachconsisting of 4 symbols are formed by a total of 12 samples (24 symbols)of digital audio data of two channels. 33 symbols (264 data bits)obtained by adding one symbol of a subcode to those total of 32 symbolsare handled as one group. That is, 33 symbols comprising the subcode of1 symbol, data of 24 symbols, the Q parity of 4 symbols, and the Pparity of 4 symbols are included in one frame obtained after the EFMmodulation.

In an EFM modulation system (eight to fourteen modulation: EFM), eachsymbol (8 data bits) is converted into 14 channel bits. A minimum timewidth (a time width in which the number of 0 between 1 and 1 of arecording signal becomes the minimum) Tmin of the EFM modulation isequal to 3 T. A pit length corresponding to 3 T is equal to 0.87 μm. Apit length corresponding to T is the shortest pit length. Coupling bitsof 3 bits are arranged between the 14 channel bits and the 14 channelbits. Further, a frame sync pattern is added to the head of the frame.Assuming that a period of the channel bits is equal to T, the frame syncpattern is set to a pattern in which 11 T, 11 T, and 2 T continue. Sincesuch a pattern does not occur in an EFM modulation rule, this peculiarpattern enables the frame sync to be detected. The total number of bitsof one frame is equal to 588 channel bits. A frame frequency is set to7.35 kHz.

A frame group comprising 98 frames as mentioned above is called asubcode frame (or a subcode block). The subcode frame expressed byrearranging those 98 frames so as to be continuous in the verticaldirection comprises: a frame sync portion to identify the head of thesubcode frame; a subcode portion; data; and a parity portion. Thesubcode frame corresponds to 1/75 second of a reproducing time of theordinary CD.

The subcode portion is constructed by 98 frames. Each of two head framesin the subcode portion is a sync pattern of the subcode frame and is apattern of an (out of rule) of the EFM. The bits in the subcode portionconstruct the P, Q, R, S, T, U, V, and W channels, respectively.

The R to W channels are used for a special application such as stillimage, character display of what is called KARAOKE, or the like. The Pand Q channels are used for the track position control operation of apickup upon reproduction of digital data recorded on the disc.

The P channel is used to record a signal of “0” in what is called alead-in area locating in a disc inner rim portion and to record a signalin which “0” and “1” are repeated at a predetermined period in what iscalled a lead-out area locating in a disc outer rim portion. In aprogram area locating between the lead-in area and the lead-out area ofthe disc, the P channel is used to record a signal in which an intervalbetween music pieces is set to “1” and the other portions are set to“0”. Such a P channel is provided to search for a head of each musicpiece upon reproduction of digital audio data recorded on the CD.

The Q channel is provided to enable finer control upon reproduction ofthe digital audio data recorded on the CD. As shown in FIG. 7, astructure of one subcode frame in the Q channel comprises: a sync bitportion 11; a control bit portion 12; an address bit portion 13; a databit portion 14; and a CRC bit portion 15.

The sync bit portion 11 consists of data of 2 bits and a part of theforegoing sync pattern has been recorded there. The control bit portion12 consists of data of 4 bits and data such as the number of audiochannels, emphasis, digital data, and the like has been recorded there.When the data of 4 bits is equal to “0000”, it indicates the audiosignal of two channels without a preemphasis. When it is equal to“1000”, it indicates the audio signal of four channels without apreemphasis. When it is equal to “0001”, it indicates the audio signalof two channels with the preemphasis. When it is equal to “1001”, itindicates the audio signal of four channels with the preemphasis. Whenthe data of 4 bits is equal to “0100”, it indicates the non-audio datatrack. The address bit portion 13 consists of data of 4 bits and acontrol signal showing a format (mode) and a type of data in the databit portion 14, which will be explained hereinafter, has been recordedthere. The CRC portion 15 consists of data of 16 bits and data forperforming error detection of a cyclic code (Cyclic Redundancy Checkcode: CRC) has been recorded there.

The data bit portion 14 consists of data of 72 bits. When the data of 4bits in the address bit portion 13 is equal to “0001” (that is, Mode 1),the data bit portion 14 has a construction in which a time code(position information) as shown in FIG. 8 is recorded. That is, the databit portion 14 is constructed by: a track number portion (TNO) 21; anindex portion (INDEX) 22; an elapsed time portion (comprising a minutecomponent portion (MIN) 23, a second component portion (SEC) 24, and aframe number portion (FRAME) 25); a zero portion (ZERO) 26; and anabsolute time portion (comprising a minute component portion (AMIN) 27,a second component portion (ASEC) 28, and a frame number portion(AFRAME) 29). Each of those portions consists of data of 8 bits.

The track number portion (TNO) 21 is expressed by a binary coded decimalnotation (Binary Coded Decimal: BCD) of 2 digits. The track numberportion (TNO) 21 shows the number of the lead-in track as a track wherethe reading operation of the data is started at “00”. Each of “01” to“99” indicates the track number corresponding to the number of eachmusic piece, movement, or the like. The track number portion (TNO) 21also shows the number of the lead-out track as a track in which thereading operation of the data is finished at “AA” of the hexadecimalnotation.

The index portion (INDEX) 22 is expressed by the BCD of two digits, “00”indicates a temporary stop, what is called “pause”, and each of “01” to“99” indicates a track portion obtained by further finely dividing thetrack of each music piece, movement, or the like.

Each of the minute component portion (MIN) 23, the second componentportion (SEC) 24, and the frame number portion (FRAME) 25 is expressedby the BCD of two digits. The elapsed time (TIME) in each music piece ormovement is shown by six digits in total. In the zero portion (ZERO) 26,“0” is added to all of 8 bits.

Each of the minute component portion (AMIN) 27, the second componentportion (ASEC) 28, and the frame number portion (AFRAME) 29 is expressedby the BCD of two digits. The absolute time (ATIME) from the first musicpiece is shown by six digits in total.

As shown in FIG. 9, a structure of the data bit portion 24 in a TOC(Table of Contents) in the lead-in area of the disc is constructed by: atrack number portion (TNO) 31; a point portion (POINT) 32; an elapsedtime portion (comprising a minute component portion (MIN) 33, a secondcomponent portion (SEC) 34, and a frame number portion (FRAME) 35); azero portion (ZERO) 36; and an absolute time portion (comprising aminute component portion (PMIN) 37, a second component portion (PSEC)38, and a frame number portion (PFRAME) 39). Each of those portionsconsists of data of 8 bits.

Each of the track number portion (TNO) 31 and the minute componentportion (MIN) 33, the second component portion (SEC) 34, and the framenumber portion (FRAME) 35 in the elapsed time portion is fixed to “00”by the hexadecimal notation. In the zero portion (ZERO) 36, “00” isadded to all of 8 bits in a manner similar to the zero portion (ZERO) 26mentioned above.

In the absolute time minute component portion (PMIN) 37, when the pointportion (POINT) 32 is equal to “A0” by the hexadecimal notation, itindicates the number of the first music piece or movement. When thepoint portion (POINT) 32 is equal to “A1” by the hexadecimal notation,it indicates the number of the first music piece or movement. When thepoint portion (POINT) 32 is equal to “A2” by the hexadecimal notation,each of the absolute time minute component portion (PMIN) 37, theabsolute time second component portion (PSEC) 38, and the absolute timeframe number portion (PFRAME) 39 indicates the absolute time (PTIME) atwhich the lead-out area starts. Further, when the point portion (POINT)32 is expressed by the BCD of 2 digits, in each of the absolute timeminute component portion (PMIN) 37, the second component portion (PSEC)38, and the frame number portion (PFRAME) 39, an address in which eachmusic piece or movement shown by its numerical value starts is shown bythe absolute time (PTIME).

As mentioned above, in the Q channel, although the format in the programarea of the disc and that in the lead-in area slightly differ, the timeinformation shown by 24 bits is recorded in both of those areas. In thesubcode of the Q channel of Mode 1 shown in FIG. 8, such a conditionthat 9 or more subcode frames are included in any 10 continuous subcodeframes on the disc has been predetermined on the standard of the CD. Asmentioned above, the subcode frame corresponds to 98 continuous frameswhich construct one delimiter of the subcode in which the two headframes are set to the sync pattern.

In the case of the subcode in the modes of Mode 2 to Mode 5 other thanMode 1, it is specified that it is sufficient that one or more framesexist in 100 continuous subcode frames. Mode 2 and Mode 3 are used forrecording a UPC/EAN (Universal Product Code/European Article Number)code and an ISRC (International Standard Recording Code) code. Mode 4 isused for a CDV. Mode 5 is used for the lead-in area of a CD-EXTRA ofmultisession. Therefore, the above explanation about Modes 1 to 3 isactually sufficient in consideration of the subcodes in the Q channelsof Mode 1, Mode 2, and Mode 3 and an explanation about Mode 4 and Mode 5is omitted hereinbelow.

As mentioned above, in the embodiment of the invention, by irradiatingthe laser beam to the reflective film, the change in reflectance iscaused and the UDI is recorded. The UDI comprises stamper-unique firstdata and disc-unique second data and is information for identifying eachdisc. For example, the first data includes a name of a discmanufacturer, a name of a disc seller, a name of a manufacturingfactory, a manufacturing year, and the like. For example, the seconddata includes a serial number, time information, and the like. In theembodiment, the UDI is recorded in a data format of the Q channel of thesubcode. Therefore, the UDI can be regarded as a new mode of the Qchannel of the subcode. Mode 7 is defined here as a mode of the Qchannel for recording the UDI.

In the case where the UDI is constructed by the first and second data asmentioned above, if all data of the UDI is recorded by the recordingmethod for the reflective film, a data amount of the UDI cannot beincreased because it is necessary to record within a limited time. Inthe embodiment, therefore, the stamper-unique first data is recorded asa concave/convex pattern and the disc-unique second data is recorded byusing the recording method for the reflective film. Further, in theembodiment, after the manufacturing, arbitrary data (third data) can berecorded onto the disc by the recording method for the reflective film.The actual recording operation is executed in a record shop, a rentalshop, or the like equipped with a dedicated recording apparatus. Thearbitrary data includes a code of a shop name, the number of rentaltimes, a user ID, and the like.

In the following description, the method of recording the concave/convexpattern by the mastering step is called “prepressing” and the additionalrecording method for the reflective film is called “prerecording”. Amain body portion of the UDI data is called “payload”. The payload whichis prepressed and the payload which is prerecorded are generally called“P-payload”. A main body portion of the third data which is recordedlater is called “R (Recordable)-payload”. Further, a payload as a headeris called “payload 0”.

FIG. 10A shows a data format of the UDI constructed by the subcode frameconsisting of 98 frames. Since the UDI is recorded in the format of theQ channel of the subcode, one frame (98 bits) of the subcode isconstructed by: a sync bit portion of 2 bits; a control bit portion(CTL) of 4 bits; an address bit portion (ADR) of 4 bits; a data bitportion of 72 bits; and a CRC of 16 bits. 4 bits of the address bitportion are set to a value showing Mode 7.

In a data area of 72 bits, the head 8 bits indicate a UDI index and theresidual 64 bits correspond to the data main body (payload) of the UDI.The data format shown in FIG. 10A is common to both of the P-payload andthe R-payload. FIG. 10B shows a data format of payload 0 as a header.The subcode frame including payload 0 has been recorded by prepressing.

As shown in FIG. 11A, the UDI index comprises: a payload number (6 bits)showing the number of the payload; and a payload status (2 bits). Thepayload number is a value which is incremented from 1. For example, theminimum number of payloads is set to 1 and the maximum number ofpayloads is set to 63. In the case of payload 0, the payload number isset to 0. The payload number and the payload status have been defined asshown in FIG. 11B. The definition of the payload status is shown below.

-   -   00: Header and prepressed P-payload    -   01: Prerecorded P-payload    -   10: Recorded R-payload (has already been recorded)    -   11: Unrecorded R-payload

That is, the payload status of 2 bits is an identifier for thesubsequent payload.

The UDI is recorded in, for example, a UDI area provided in the programarea on the disc. An area of the prepressing payload, an area of theprerecording payload, and an area of the recordable payload are providedin order in the UDI area. Payload 0 is recorded as a UDI header in thehead of the UDI area.

FIG. 12A shows the data format of payload 0. The subcode frame includingpayload 0 has been recorded by prepressing. A last payload number (6bits), a prepressing payload start number (6 bits), a prerecordingpayload start number (6 bits), a recordable payload start number (6bits), an error correction (1 bit), a security (3 bits), and an ECC (16bits) are included in payload 0. The residual 20 bits are not definedand can be defined in the future. The payload number of payload 0 is setto 0.

FIG. 12B shows a value of each field of payload 0. A value of the lastpayload number can be set to a value within a range from 1 to 63. Eachof the prepressing payload start number, the prerecording payload startnumber, and the recordable payload start number can be set to a valuewithin a range from 0 to 63. When such a value is equal to 0, it meansthat no payload exists.

When the error correction (1 bit) is equal to a value “0”, it means thatthe ECC is not performed. When it is equal to a value “1”, it means thatthe ECC has been performed. When a value of the security is equal to(000), this means that it denotes “non-secure”. When it is equal to(100), this means that it denotes “secure”. Other values are not definedyet. The ECC is set to either an ECC parity (the case of the errorcorrection=“1”) or zero data (the case of the error correction=“0”).

FIGS. 13A and 13B show data formats of the P-payload. The data format inthe case where there is no ECC is shown in FIG. 13A. The data format inthe case where the ECC exists is shown in FIG. 13B.

FIGS. 14A and 14B show data formats of the R-payload. The data format inthe case where there is no ECC is shown in FIG. 14A. The data format inthe case where the ECC exists is shown in FIG. 14B. At a stage where thedata has been formed by mastering, a payload field, an ECC field (in thecase where the ECC is applied), and a CRC field are set to “1”,respectively. An initial value of the CRC of 16 bits is set to 0. TheCRC of 16 bits is calculated from the data (control CTL, address ADR,UDI index, and payload) shown in FIG. 10A and a calculation result isinserted as AUX. When recording is executed, a CRC is calculated inaccordance with data to be recorded and a calculation result is recordedinto the CRC. Such a process is executed to enable the correct result ofthe CRC detection to be obtained if there is no error at both timingbefore and after the recording to the R-payload.

FIG. 15 is a diagram for more schematically explaining the additionalrecording method of the UDI. A frame sync is set to a length of 24 bits(channel bits), an inverting interval is set to 11 T and 11 T, and 2 Tis added after that. A pattern can be set to either a pattern A or apattern B in dependence on a corresponding method of two 11T, the pit,and the land. First, the pattern A will be described.

Coupling bits (000) of 3 bits are inserted between the symbols of theframe sync and the subcode. In the case of recording the UDI, thesubcode symbol on the optical disc molded by stamping is set to (0x47).“0x” denotes the hexadecimal notation. A pattern (00100100100100) of 14bits as a result obtained by EFM modulating those 8 bits is shown inFIG. 15.

The laser beam for additional recording is irradiated into a hatchedregion between two pits. Thus, reflectance in the hatched regiondeteriorates. After the recording, those two pits are reproduced as onecoupled pit. A pattern of 14 bits in this case becomes (00100100000000).If it is EFM demodulated, it is demodulated as 8 bits of (0x07).

In the case of the pattern B in which 11 T on the front side is the landand 11 T on the rear side is the pit, coupling bits are (001). Also inthis case, by irradiating the laser beam into a hatched region, 8 bitsof the subcode can be changed from (0x47) to (0x07) in a manner similarto the pattern A.

As shown in FIG. 16A, in 96 frames other than the head 2 frames whichare used as frames of the sync signal among 98 frames, 8 bits of thesubcode correspond to the bits of the channels P, Q, R. S, T, U, V, andW, respectively. Therefore, as will be obviously understood from FIG.16A, the operation to change 0x47 to 0x07 is equivalent to such anoperation that only the bits in the channel Q are changed to “1” or “0”without changing the bits in the channels other than the channel Q.Therefore, all bits of the data which is prerecorded are equal to “1”before recording and only the portions where the laser beam has beenirradiated are set to “0”.

FIG. 16B shows another example of the additional recording method. Itrelates to the example in which when the bit of the UDI is equal to “0”,8 bits of the subcode are changed from (0x40) to (0x00). Also in suchanother example, only the bits in the channel Q can be changed to “1” or“0” without changing the bits in the channels other than the channel Q.

Further, in the examples of FIGS. 16A and 16B, the channel P is set tothe value of “0”. The channel P is set to “1” in the case of an intervalbetween music pieces and to “0” in the case of an inside of music piecedata. Since the interval between the music pieces is short to be about 2to 3 seconds, there is a case where if a reproducing apparatusdetermined that a reproducing portion corresponds to the intervalbetween the music pieces, the reproducing apparatus does not read outthe subcode recorded in such an interval. Therefore, the intervalbetween the music pieces is improper as a location where the UDI isrecorded. As mentioned above, by setting P=“0”, the UDI can be recordedinto the portion of the music piece.

The UDI area where the UDI has been recorded is formed at the fixedposition on the disc. As an additional recording method for thereflective film, in the case of using a method of recording by rotatingthe disc at a one-time speed, if the UDI is recorded into the wholeprogram area of the disc, a time that is required for recording becomeslong. Therefore, for example, the UDI area is provided for the headportion of the program area and the UDI is recorded there.

According to the standard of the CD, the ratio has been specified withrespect to the Q channel of the subcode That is, as mentioned above, inthe subcode of Mode 1, it is necessary that 9 or more subcode frames areincluded in any 10 continuous subcode frames on the disc. It has alsobeen specified that in the case of the subcodes of Mode 2 and Mode 3other than Mode 1, it is sufficient that one or more subcode framesexist in 100 continuous subcode frames.

A recording method which can record the UDI to the fixed position whilesatisfying such a standard of the ratio will now be described. FIG. 17shows an example of a recording layout of the UDI. The UDI is set to asubcode of Mode 7. Payload 0 is recorded in the head of the UDI area. Inthe case of recording payload 0 and other payloads, they aremultiple-written for the purpose of taking a countermeasure againsterrors. In the example of FIG. 17, quintuple-recording is performed.Payload 1 is recorded after payload 0. In the case of performing thequintuple-recording, the payloads of the same payload number arecollectively quintuple-recorded.

In the CD or the like, after the program area starts and a silentportion (interval between the music pieces) shown by the track=01 andthe index=00exists for about two seconds, the first music piece isstarted from track start time S. The UDI is recorded from the positionafter one second from the track start time S. The payloads are arrangedin positions (S+00 (minute):01 (second):00 (frame), S+00:01:12, . . . )of intervals of 12 frames (which denote the subcode frames). The subcodeof Mode 1 can be recorded in the position where no UDI is recorded. Thefirst subcode frame of payload 1 is recorded in the position of(S+00:01:60). Areas of 9 subcode frames before the recording position ofthe first payload and 9 subcode frames after the last payload are areaswhere the subcodes of Mode 1 are recorded. Since importance of Mode 1 ishigher than those of other Mode 2 and Mode 3, it must not infringe thestandard of the ratio regarding Mode 1. However, it is not alwaysnecessary to satisfy the standard of the ratio regarding Mode 2 or Mode3 according to circumstances. For example, the recordable area of Mode 2or Mode 3 can be omitted.

The numerical values of the subcode frames in the recording layout shownin FIG. 17 are shown as an example and other various numerical valuescan be used. However, the interval for arranging the data of thepayloads to be multiple-written is set so that a plurality of data (5data here) to be multiple-written is widely distributed on the trackbecause they are not arranged in the radial direction of the disc asdescribed with reference to FIG. 1 or 2. The foregoing interval of 12frames satisfies such a condition.

A length of circumference (one circumference of the track) is determinedin accordance with the position on the disc where the UDI is recorded.For example, when the recording position is set to a positioncorresponding to a diameter of about 50 to 51 mm, one circumference isequal to about 157.1 to 160.2 mm. One subcode frame (1 sector) is equalto 1/75 (sec). In the CD, since a linear velocity is constant to be, forexample, 1.2 (m/sec), a displacement of a period of 1/75 (sec) is equalto 16 mm. Therefore, the intervals corresponding to 10 frames, 11frames, 12 frames, and 13 frames are equal to 160 mm, 176 mm, 192 mm,and 208 mm, respectively.

Among those values, 160 mm in the case of 10 frames is equal to thelength of almost one circumference. If the interval is set to 10 frames,five payloads to be multiple-written are arranged in the diameterdirection of the disc, so that the error resistance becomes weak. In thecase of the quintuple-writing, a value (192 mm) which is 1.2 times aslarge as 160 mm is preferable because the data interval is widened. Thevalue in the case of the interval of 12 frames mentioned above is equalto 192 mm. In the embodiment, therefore, the interval of the data whichis quintuple-written is set to 12 frames.

If the recording position of the UDI, the number (n) of multiple-writingtimes, or the linear velocity differs, the numerical value of the datainterval is set to a value other than 12 frames. Even if the linearvelocity is equal to 1.15 (m/sec) and slightly deviated from thestandard, the data can be reproduced by the existing CD player or CD-ROMdrive. In the case of such a linear velocity, it is also possible thatonly one of the intervals among the five data to be quintuple-written isset to a value larger than 12 frames. That is, the intervals are notlimited to the equal intervals.

FIG. 18 shows an example of a construction of a mastering apparatus forforming the data recording medium according to the invention. Themastering apparatus has: a laser 51 as a gas laser such as Ar ion laser,He—Cd laser, Kr ion laser, or the like or a semiconductor laser; a lightmodulator 52 of an acousto-optical effect type or an electro-opticaltype for modulating a laser beam emitted from the laser 51; and anoptical pickup 53 as recording means having an objective lens or thelike for converging the laser beam which passed through the lightmodulator 52 and irradiating it onto a photoresist surface of adisc-shaped glass mother disc 54 coated with a photoresist as aphotosensitive material.

The light modulator 52 modulates the laser beam from the laser 51 inaccordance with the recording signal. By irradiating the modulated laserbeam onto the glass mother disc 54, the mastering apparatus forms amaster on which the data has been recorded. A servo circuit (not shown)for controlling so as to keep a distance between the optical pickup 53and the glass mother disc 54 constant, controlling tracking, andcontrolling the rotation driving operation of a spindle motor 55 isprovided. The glass mother disc 54 is rotated by the spindle motor 55.

The recording signal from an adder 74 is supplied to the light modulator52. Main digital data to be recorded is supplied from input terminals 61a and 61 b. The data from the input terminal 61 a is converted into datain a format of the CD-ROM by a CD-ROM encoder 75 and supplied to a CIRC(Cross Interleave Reed-Solomon Code) encoder 67. The data which isinputted to the input terminal 61 b has the CD-ROM format and issupplied to the CIRC encoder 67 without passing through the CD-ROMencoder 67.

The CIRC encoder 67 executes an error correction encoding process foradding parity data or the like for error correction or a scramblingprocess. That is, the error correction encoding process by which 16 bitsof one sample or one word are divided into upper 8 bits and lower 8bits, these 8 bits are set to one symbol, respectively, and the paritydata or the like for error correction by, for example, the CIRC is addedon such a symbol unit basis or the scrambling process is executed.

The subcodes in the channels P to W based on the existing CD standard(called ordinary subcodes) are supplied from an input terminal 62. Thesubcodes of not only Mode 1 but also Mode 2 and Mode 3 are included inthe ordinary subcodes. Prepressing UDI data is supplied from an inputterminal 63. The prepressing UDI data is data including thestamper-unique prepressing payload.

Prerecording UDI data is supplied from an input terminal 64. RecordableUDI data is supplied from an input terminal 65. The payloads included ineach of the prerecording UDI data and the recordable UDI data are basedon the data of (0x47) or (0x40) as mentioned above and are the data ofall “1”. Further, a frame sync is supplied from an input terminal 66.The data from the input terminals 62, 63, 64, and 65 is supplied toinput terminals (a, b, c, and d) of a switching circuit 68,respectively. The data selected by the switching circuit 68 is convertedinto data in a frame format of the subcode by a subcode encoder 70. Aswitching signal from a switching signal generator 71 is supplied to theswitching circuit 68 and the subcode encoder 70.

The switching signal generator 71 generates the switching signal on thebasis of an instruction signal from a controller (shown by a CPU in thediagram) for controlling the frame sync and the whole masteringapparatus. As mentioned above, the position of the UDI area is set tothe fixed position on the disc and the position where the UDI data(subcode of Mode 7) is recorded in the UDI area is also fixed. The framesync is used for setting the interval or the like in the case of themultiple-writing into a predetermined value. The subcode encoder 70converts the data extracted to an output terminal (e) of the switchingcircuit 68 in accordance with the switching signal into data in asubcode format.

In the data format shown in FIG. 10A, the sync bits, control bits,address bits, and UDI index can be recorded by the recording method forthe reflective film or can be also recorded as a concave/convex patternby prepressing. Since the CRC bits are calculated in accordance with thepayloads which are recorded, they cannot be recorded by prepressing. Asshown in AUX (refer to FIG. 14) mentioned above, by designating thevalues of 16 bits in the payload, it is also possible to prevent thegeneration of CRC errors even if all of the inherent CRC bits are equalto “1”.

The main data from the CIRC encoder 67 and an output of the subcodeencoder 70 are mixed by an adder 69. An output of the adder 69 issupplied to an EFM modulator 73 and the symbol of 8 bits is convertedinto data of 14 channel bits in accordance with a conversion table. Anoutput of the EFM modulator 73 is supplied to the adder 74. The framesync from the input terminal 66 is supplied to the adder 74. Therecording signal in the frame format mentioned above is generated fromthe adder 74. This recording signal is supplied to the light modulator52 and the photoresist on the glass mother disc 54 is exposed by themodulated laser beam from the light modulator 52. The glass mother disc54 which has been recorded as mentioned above is developed and subjectedto the electroforming process, thereby forming a metal master.Subsequently, a mother disc is formed from the metal master. Further,subsequently, a stamper is formed from the mother disc. An optical discis formed by using the stamper by the method such as compressionmolding, injection molding, or the like. Although the optical disc issimilar to the ordinary CD, the material of the reflective film isproperly selected so that the UDI can be additionally recorded asmentioned above.

FIG. 19 shows an example of a construction of a recording/reproducingapparatus for additionally recording the UDI data onto the optical discformed by the mastering and stamping mentioned above. As UDI data whichis additionally recorded, there are both of the prerecording payload andthe recordable payload. According to the construction of FIG. 13, bothof them can be recorded. However, it is not always necessary that bothof them can be recorded but it is also possible to enable only eitherone of them to be recorded.

In FIG. 19, reference numeral 81 denotes a disc formed by the masteringand stamping steps; 82 a spindle motor for rotating the disc 81; and 83an optical pickup for reproducing a signal recorded on the disc 81 andrecording the UDI thereon. The optical pickup 83 comprises: an opticalsystem such as semiconductor laser, objective lens, and the like forirradiating a laser beam onto the disc 81; a detector for detectingreturn light from the disc 81; a focusing and tracking mechanism; andthe like. A laser power is switched in accordance with the recordingmode or the non-recording mode. In the recording mode, the laser of apower necessary for causing a change in reflectance in the reflectivefilm is used. In the non-recording mode, the laser of a power necessaryfor reading out information recorded on the disc 81 is used. Further,the optical pickup 83 is sent in the radial direction of the disc 81 bya sled mechanism (not shown).

Output signals from, for example, a 4-split detector of the opticalpickup 83 are supplied to an RF unit 84. The RF unit 84 arithmeticallyoperates the output signals of four detectors of the 4-split detector,thereby forming a reproduction (RF) signal, a focusing error signal, anda tracking error signal, respectively. The reproduction signal issupplied to a sync detecting unit 85. The sync detecting unit 85 detectsa frame sync added to the head of each frame. The detected frame syncs,the focusing error signal, and the tracking error signal are supplied toa servo circuit 86. The servo circuit 86 controls the rotating operationof the spindle motor 82 and controls a focusing servo and a trackingservo of the optical pickup 83 on the basis of a reproduction clock ofthe RF signal.

The main data which is outputted from the frame sync detecting unit 85is supplied to an EFM demodulator 88 through a subcode detector 87 andsubjected to an EFM demodulating process. The main digital data from theEFM demodulator 88 is extracted to an output terminal (not shown) asnecessary. The subcode data from the EFM demodulator 88 is supplied to asubcode decoder 89. The subcode decoder 89 collects the 8-bit subcodesof each frame of the number of 98 frames, thereby constructing data ofthe subcode frame.

A detector 90 of the UDI area and payload 0 is connected to an output ofthe subcode decoder 89. The detector 90 detects the data of payload 0from the payload area and makes error correction based on themultiple-recording of the data of payload 0. The construction of the UDIarea can be recognized from the data of payload 0 and the recordingposition of the prerecording payload or the recordable payload can berecognized. Information from the detector 90 is supplied to a UDIencoder 92 and a subcode encoder 93.

Data from an input terminal 91 is supplied to the UDI encoder 92. TheUDI encoder 92 generates the payload of the UDI. It is converted intothe format of the subcode by the subcode encoder 93. An output of thesubcode encoder 93 is supplied to an input terminal (f) of a switchingcircuit 94. The switching circuit 94 is controlled by an output of thedetector 90. In the case of recording the prerecording payload, anoutput terminal (g) is selected. In the case of recording the recordablepayload, an output terminal (h) is selected.

The data of the prerecording payload from the output terminal (g) of theswitching circuit 94 is supplied to a recording unit 95. The data of therecordable payload from the output terminal (h) is supplied to arecording unit 96. The subcode from the subcode detector 87 is suppliedto the recording units 95 and 96. Outputs of the recording units 95 and96 are supplied to the optical pickup 83. In the case where the subcoderecorded as 0x47 (or 0x40) is changed to 0x70 (or 0x00), the recordingunits 95 and 96 generate outputs for changing the laser power into therecording power.

The construction shown in FIG. 19 can be changed to a possibleconstruction in accordance with whether the whole one frame of 98 bitsis recorded or a part thereof is recorded by prepressing. Further, ifthe UDI area has been set to the fixed position, since the prerecordingposition and the layout of the recordable area can be known, it ispossible to determine the recording position by referring to thereproduced subcode (time code) and record the data to the determinedposition.

The invention is not limited to the foregoing embodiments or the like ofthe invention but many variations and modifications are possible withinthe scope of the invention without departing from the spirit of theinvention. For example, the UDI area is not limited to the program areaof the disc but can be provided in the lead-in area. The UDI is anexample of the data which is multiple-written and the invention can bealso applied to the case of multiple-writing data other than the UDI.

The invention can be also applied to, for example, an optical disc ofmultisession for recording data in the format of the CD-DA and data inthe format of the CD-ROM. As information which is recorded to theoptical disc, various data such as audio data, video data, still imagedata, character data, computer graphics data, game software, computerprogram, and the like can be recorded. Further, the invention can bealso applied to, for example, a DVD video and a DVD-ROM.

DESCRIPTION OF REFERENCE NUMERALS

-   2 REFLECTIVE FILM-   51 LASER-   53 OPTICAL PICKUP-   54 GLASS MOTHER DISC-   62 INPUT TERMINAL OF ORDINARY SUBCODE-   63 INPUT TERMINAL OF PREPRESSING UDI DATA-   64 INPUT TERMINAL OF PRERECORDING UDI DATA-   65 INPUT TERMINAL OF RECORDABLE UDI DATA-   81 DISC FORMED BY MASTERING-   S1 FORM MASTERING MASTER-   S2 FORM METAL MASTER-   S3 FORM MOTHER-   S4 FORM STAMPER-   S5 FORM DISC SUBSTRATE-   S6 FORM REFLECTIVE FILM AND PROTECTIVE FILM-   S7 RECORD ONTO REFLECTIVE FILM

1. An optical recording medium configured to provide data structured persub-code frame for cooperating with a recording/reproducing device toprovide managed access to the structured data, and, having two or moregroups of sub-code frames spirally or concentrically recorded thereon,comprising: a first and second subcode data recorded in a plurality oflocations on the medium, identical first and second subcode data beingrepetitively recorded at locations in a circumferential direction atsubstantially equal distances apart from each other around an entirecircumference of the medium, including data for uniquely identifying therecording medium, the intervals at which the first and second subcodedata are recorded corresponding to a linear velocity for accessing themedium via the recording/reproducing device.
 2. The recording mediumaccording to claim 1, wherein the second subcode data is expressed onthe recording medium as pre-pressed pits and lands which serve as acomponent of a unique disc identifier (UDI) which identifies a masteringapparatus.
 3. The recording medium in accordance with claim 1, whereinthe first subcode data is expressed on the recording medium as avariance in reflectance of a reflective film of the recording medium,the variance being a component of a unique disc identifier (UDI) toidentify the recording medium.
 4. The recording medium in accordancewith claim 1, wherein the recording medium is a disc encoded with errordetection and error correction data.
 5. The recording medium inaccordance with claim 1, wherein the subcode is provided in a compactdisc (CD) format.
 6. The recording medium in accordance with claim 5,wherein the repetitive recording is five repetitions at intervals oftwelve sub-code frames.
 7. The recording medium of claim 5, wherein thefirst and second subcode data are recorded in a Q channel of the two ormore groups of sub-code frames.
 8. The recording medium of claim 1,wherein the medium is rectangular and the second subcode data isarranged on one side of the medium at regular intervals.
 9. Arecording/reproducing device configured to access a recording mediumwhich includes data structured per sub-code frame, and, having two ormore groups of sub-code frames spirally or concentrically recordedthereon, comprising: a read/write unit configured to access a first andsecond subcode data recorded in a plurality of locations on the medium,identical first and second subcode data being repetitively recorded atlocations in a circumferential direction at substantially equaldistances apart from each other around an entire circumference of themedium, including data for uniquely identifying the recording medium,the intervals at which the first subcode data are recorded correspondingto a linear velocity for accessing the medium.
 10. Therecording/reproducing device according to claim 9, wherein therecording/reproducing device identifies the second subcode data aspre-pressed pits and lands.
 11. The recording/reproducing device mediumin accordance with claim 9, wherein the read/write unit writes the firstsubcode data to the recording medium as a variance in reflectance of areflective film of the recording medium to identify the recordingmedium.
 12. The recording/reproducing device in accordance with claim11, wherein the first subcode is provided to a Q channel of the two ormore groups of sub-code frames, the sub-code frames being provided in acompact disc (CD) format.